Military Communications Satellites

As soon as the possibility of placing a man-made satellite into an Earth orbit was recognized,
speculation began as to the feasibility of using a radio repeater (transponder) for intercontinental
communications. The use of geostationary satellites for this purpose was suggested by Arthur C.
Clarke in an article in "Wireless World", 1946. The advantages of the geostationary orbit for
general communications and for broadcasting was apparent, although there was much speculation
about the acceptability of satellite links for telephone channels in view of the long echo delay of
some 540 milliseconds. A public offering of satellite voice channels was not made until sixteen
years later at which time they were found to be acceptable as had indeed been predicted by
simulated tests.

There are four segments to the military satellite communications (MILSATCOM)
architecture. First, ultrahigh frequency (UHF) satellites are the workhorses for
tactical ground, sea, and air forces. Second, the superhigh frequency (SHF)
Defense Satellite Communications System (DSCS), first deployed in the 1970s,
supports long-distance communications requirements of military forces that
cannot be met by groundbased communications systems. The DSCS system
satisfies the majority of DoD's medium- and high data-rate communications
requirements. Milstar will soon be integrated as the third segment of the
MILSATCOM architecture. It will provide a worldwide, secure, jam-resistant
communications capability to US civilian and military leaders for command and
control of military forces. The fourth segment consists of commercial
communications satellites, which are used to support DoD's MILSATCOM
capabilities where jamming protection is not required.(1)

In 1945 British scientist and science fiction writer, Arthur C. Clarke, published
a technical paper in which he suggested that communications satellites were
feasible.

The Syncoms were three experimental, active satellites. The name, coined from
the first syllables of "synchronous communications," referred to their orbits. Each
Syncom satellite weighed about 85 pounds. Syncom I was launched February 14,
1963, but did not reach synchronous orbit and communications failed. Syncom II,
launched July 26, 1963, was the first satellite placed in synchronous orbit. It
was active in many successful intercontinental communication experiments.
Syncom III, launched August 19, 1964, was the first stationary Earth satellite.
It demonstrated the practicality and effectiveness of stationary, active
communication satellites. In orbit near the International Date Line, it was used
to telecast the 1964 Olympic Games in Tokyo to the United States, the first
television program to cross the Pacific.

References

1. Department of Defense, Report on the Bottom Up Review, October 1993, page
65.